An explanation using an integrated set of principles that organizes observations and predicts behaviours or events.

Hypothesis

A testable prediction, often implied by a theory.

Operational Definition

A statement of the procedures used to define research variables. For example, human intelligence may be what an intelligence test measures.

Replication

Repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances.

Case Study

An observation technique in which one person is studied in depth in the hope of revealing universal principles.

Survey

A technique for ascertaining the self-reported attitudes or behaviors of people, usually by questioning a representative, random sample of them.

False Consensus Effect

The tendency to overestimate the extent to which others share our beliefs and behaviors.

Population

All the cases in a group, from which samples may be drawn for a study.

Random Sample

A sample that fairly represents a population because each member has an equal chance of inclusion.

Naturalistic Observation

Observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation.

Correlation

A measure of the extent to which two factors vary together, and thus of how well either factor predicts the other. The... coefficient is the mathematical expression of the relationship, ranging from -1 to +1.

Scatterplot

A graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation (little scatter indicates high correlation).

Illusory Correlation

The perception of a relationship where none exists.

Experiment

A research method in which an investigator manipulates one or more factor (independent variables) to observe the effect on some behavior or mental process (the dependent variable). By random assignment of participants, the researcher aims to control other relevant factors.

Single-Blind Experiment

An experimental procedure in which the research participants are ignorant about whether the research participants have received the treatment or a placebo, but the experimenters know which is which.

Double-Blind Experiment

An experimental procedure in which both the research participants and the research staff are ignorant about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies.

Experimental Condition

The part of an experiment that exposes participants to the treatment, that is, to one version, of the independent variable.

Placebo Effect

Experimental results caused by expectations alone; any effect on behaviour caused by the administration of an inert substance or condition, which is assumed to be an active agent.

Control Condition

The part of an experiment that contrasts with the experimental condition and serves as a comparison for evaluating the effect of the treatment.

Random Assignment

Assigning participants to experimental and control conditions by chance, thus minimizing pre-existing differences between those assigned to the different groups.

Independent Variable

The experimental factor that is manipulated; the variable whose effect is being studied.

Dependent Variable

The outcome factor; the variable that may change in response to manipulations of the independent variable.

Mode

The most frequent occurring score(s) in a distribution.

Mean

The arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores.

Median

The middle score in a distribution; half the scores are above it and half are below it.

Range

The difference between the highest and lowest scores in a distribution.

Standard Deviation

A computed measure of how much scores vary around the mean score.

Statistical Significance

A statistical statement of how likely it is that an obtained result occurred by chance.

Culture

The enduring behaviours, ideas, attitudes, and traditions shared by a large group of people and transmitted from one generation to the next.

The bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body.

Axon

The extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscle or glands.

Myelin Sheath

A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.

Action Potential

A neural impulse; a brief electrical charge that travels down an axon. It is generated by the movement of positively charged atoms in and out of channels in the axon's membrane.

Threshold

The level of stimulation required to trigger a neural impulse.

Synapse

The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or cleft.

Neurotransmitters

Chemical messengers that traverse the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.

Acetylcholine

A neurotransmitter that enables learning and memory and also triggers muscle contraction.

Endorphins

"morphine within"- natural, opiate like neurotransmitters linked to pain control and to pleasure.

Nervous System

The body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.

Central Nervous System (CNS)

The brain and spinal cord.

Peripheral Nervous System (PNS)

The sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.

Nerves

Neural "cables" containing many axons. These bundled axons, which are part of the peripheral nervous system, connect the central nervous system with muscles, glands, and sense organs.

Sensory Neurons

Neurons that carry incoming information from the sense receptors to the central nervous system.

Motor Neurons

Neurons that carry outgoing information from the central nervous system to the muscles and glands.

Interneurons

Central nervous system neurons that internally communicate and intervene between the sensory inputs and motor outputs.

Somatic Nervous System (SNS)

The division of the peripheral nervous system that controls the body's skeletal muscles. Also called the skeletal nervous system.

Autonomic Nervous System

The part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.

Sympathetic Nervous System

The division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations.

Parasympathetic Nervous System

The division of the autonomic nervous system that calms the body, conserving its energy.

Reflex

A simple, automatic, inborn response to a sensory stimulus, such as the knee-jerk response.

The oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; it is responsible for automatic survival functions.

Medulla

The base of the brainstem; controls heartbeat and breathing.

Reticular Formation

A nerve network in the brainstem that plays an important role in controlling arousal.

Thalamus

The brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.

Cerebellum

The "little brain" attached to the rear of the brainstem; its functions include processing sensory input and coordinating movement output and balance.

Limbic System

A doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres; associated with emotions such as fear and aggression and drives such as those for food and sex. Includes the hippocampus, amygdala, and hypothalamus.

Amygdala

Two lima bean-sized neural clusters that are components of the limbic system and are linked to emotion.

Hypothalamus

A neural structure lying below (hypo) the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion.

Cerebral Cortex

The intricate fabric of interconnected neural cells that covers the cerebral hemispheres; the body's ultimate control and information-processing center.

Glial Cells

Cells in the nervous system that support, nourish, and protect neurons.

Frontal Lobes

The portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgments.

Parietal Lobes

The portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position.

Occipital Lobes

The portion of the cerebral cortex lying at the back of the head; includes the visual areas, which receive visual information from the opposite visual field.

Temporal Lobes

The portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each of which receives auditory information primarily from the opposite ear.

Motor Cortex

An area at the rear of the frontal lobes that controls voluntary movements.

Sensory Cortex

The areas at the front of the parietal lobes that registers and processes body touch and movement sensations.

Association Areas

Areas of the cerebral cortex that are not involved in primary motor or sensory functions' rather, they are involved in higher mental functions such as learning, remembering, thinking, and speaking.

Aphasia

Impairment of language, usually caused by left hemisphere damage either to Broca's area (impairing speaking) or to Wernicke's area (impairing understanding).

Broca's Area

Controls language expression- an area of the frontal lobe, usually in the left hemisphere, that directs the muscle movements involved in speech.

Wernicke's Area

Controls language reception- a brain area involved in language comprehension and expression; usually in the left temporal lobe.

Plasticity

The brain's capacity for modification, as evident in brain reorganisation following damage (especially in children) and in experiments on the effects of experience on brain development.

Corpus Callosum

The large band of neural fibers connecting the two brain hemispheres and carrying messages between them.

Split Brain

A condition in which the two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them.

Environment

Every nongenetic influence, from prenatal nutrition to the people and things around us.

Behavior Genetics

The study of the relative power and limits of genetic and environmental influences on behaviour.

Chromosomes

Threadlike structures made of DNA molecules that contain the genes.

Deoxyribonucleic Acid (DNA)

A complex molecule containing the genetic information that makes up the chromosomes.

Genes

The biochemical units of heredity that make up the chromosomes; a segment of DNA capable of synthesizing a protein.

Genome

genome: The complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes.

Identical Twins

Twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms.

Fraternal Twins

Twins who develop from separate fertilized eggs. They are genetically no closer than brothers and sisters, but they share a fetal environment.

Temperament

A person's characteristic emotional reactivity and intensity.

Heritability

The proportion of variation among individuals that we can attribute to genes. The heritability of a trait may vary, depending on the range of populations and environments studied.

Interaction

The effect of one factor (such as environment) depends on another factor (such as heredity).

Molecular Genetics

The subfield of biology that studies the molecular structure and function of genes.

Evolutionary Psychology

The study of the evolution of behavior and the mind, using principle of natural selection.

Natural Selection

The principle that, among the range of inherited trait variations, those that lead to increased reproduction and survival will most likely be passed on to succeeding generations.

Mutation

A random error in gene replication that leads to a change.

Gender

In psychology, the biologically and socially influenced characteristics by which people define male and female.

Culture

The enduring behaviours, ideas, attitudes, values, and traditions shared by a group of people and transmitted from one generation to the next.

Norm

An understood rule for accepted and expected behavior. They prescribe "proper" behavior.

Personal Space

The buffer zone we like to maintain around our bodies

Individualism

Giving priority to one's own goals over group goals and defining one's identity in terms of personal attributes rather than group identifications.

Collectivism

Giving priority to the goals of one's group (often one's extended family or work group) and defining one's identity accordingly.

Aggression

Physical or verbal behavior intended to hurt someone.

X Chromosome

The sex chromosome found in both men and women. Females have two X chromosomes; males have one. An X chromosome from each parent produces a female child.

Y Chromosome

The sex chromosome found only in males. When paired with an X chromosome from the mother, it produces a male child.

Testosterone

The most important of the male sex hormones. Both males and females have it, but the additional testosterone in males stimulates the growth of the male sex organs in the fetus and the development of the male sex characteristics during puberty.

Role

A set of expectations (norms) about a social position, defining how those in the position ought to behave.

Gender Role

A set of expected behaviors for males and for females.

Gender Identity

One's sense of being male or female.

Gender-Typing

The acquisition of a traditional masculine or feminine role.

Social Learning Theory

The theory that we learn social behavior by observing and imitating and by being rewarded or punished.

Gender Schema Theory

The theory that children learn from their cultures a concept of what it means to be male and female and that they adjust their behavior accordingly.

Developmental Psychology

A branch of psychology that studies physical, cognitive, and social change throughout the life span.

Zygote

The fertilized egg; it enters a 2-week period of rapid cell division and develops into an embryo.

Embryo

The developing human organism from about 2 weeks after fertilization through the second month.

Fetus

The developing human organism from 9 weeks after conception to birth.

Teratogens

Agents, such as chemicals and viruses, that can reach the embryo or fetus during prenatal development and cause harm.

Fetal Alcohol Syndrome

Physical and cognitive abnormalities in children caused by a pregnant woman's heavy drinking. In severe cases, symptoms include noticeable facial disproportions.

Rooting Reflex

: A baby's tendency, when touched on the cheek, to turn toward the touch, open the mouth, and search for the nipple.

Habituation

Decreasing responsiveness with repeated stimulation. As infants gain familiarity with repeated exposure to a visual stimulus, their interest wanes and they look away sooner.

Adapting one's current understands (schemas) to incorporate new information.

Cognition

All the mental activities associated with thinking, knowing, remembering, and communicating.

Sensorimotor Stage

In Piaget's theory, the stage (from birth to about 2 years of age) during which infants know the world mostly in terms of their sensory impressions and motor activities.

Object Permanence

The awareness that things continue to exists even when not perceived.

Preoperational Stage

In Piaget's theory, the stage (from about 2 to 6 years of age) during which a child learns to use language but does not yet comprehend the mental operations of concrete logic.

Conservation

The principle (which Piaget believed to be part of concrete operational reasoning) that properties such as mass, volume, and number remain the same despite changes in the forms of objects.

Egocentrism

In Piaget's theory, the preoperational child's difficulty taking another's point of view.

Theory of Mind

People's ideas about their own and others' mental states- about their feelings, perceptions, and thoughts and the behavior these might predict.

Autism

A disorder that appears in childhood and is marked by deficient communication, social interaction, and understanding of others' states of mind.

Concrete Operational Stage

In Piaget's theory, the stage of cognitive development (from about 6 or 7 to 11 years of age) during which children gain the mental operations that enable them to think logically about concrete events.

Formal Operation Stage

In Piaget's theory, the stage of cognitive development (normally beginning about age 12) during which people begin to think logically about abstract concepts.

Stranger Anxiety

The fear of strangers that infants commonly display, beginning by about 8 months of age.

Attachment

An emotional tie with another person; shown in young children by their seeking closeness to the caregiver and showing distress on separation.

Critical Period

An optimal period shortly after birth when an organism's exposure to certain stimuli or experiences produces proper development.

Imprinting

The process by which certain animals form attachments during a critical period very early in life.

Basic Trust

According to Erik Erikson, a sense that the world is predictable and trustworthy; said to be formed during infancy by appropriate experiences with responsive caregivers.

Self-Concept

A sense of one's identity and personal worth.

Adolescence

The transitional period from childhood to adulthood, extending from puberty to independence.

Puberty

The period of sexual maturation, during which a person becomes capable of reproducing.

Primary Sex Characteristics

The body structures (ovaries, testes, and external genitalia) that make sexual reproduction possible.

One's ability to reason speedily and abstractly; tends to decrease during late adulthood.

Social Clock

The culturally preferred timing of social events such as marriage, parenthood, and retirement.

Sensation

The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.

Perception

The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.

Bottom-Up Processing

Analysis that begins with the sensory receptors and works up to the brain's integration of sensory information.

Top-Down Processing

Information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations.

Psychophysics

The study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them.

Absolute Threshold

The minimum stimulation needed to detect a particular stimulus 50 percent of the time.

Signal Detection Theory

A theory predicting how and when we detect the presence of a faint stimulus ("signal") amid background stimulation ("noise"). Assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and level of fatigue.

The minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference. (Also called "just noticeable difference" or jnd.)

Weber's Law

The principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount).

Sensory Adaptation

Diminished sensitivity as a consequence of constant stimulation.

Transduction

Conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sound, and smells, into neural impulses our brains can interpret.

Wavelength

The distance from the peak of one light or sound wave to the peak of the next. Electromagnetic wavelengths vary from the short blips of cosmic rays to the long pulses of radio transmission.

Hue

The dimension of colour that is determined by the wavelength of light; what we know as the colour names blue, green, and so forth.

Intensity

The amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave's amplitude.

Pupil

The adjustable opening in the center of the eye through which light enters.

Iris

A ring of muscle tissue that forms the coloured portion of the eye around the pupil and controls the size of the pupil opening.

Lens

The transparent structure behind the pupil that changes shape to help focus images on the retina.

Accomodation

The process by which the eye's lens changes shape to focus near or far objects on the retina.

Retina

The light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information.

Acuity

The sharpness of vision.

Nearsightedness

A condition in which nearby objects are seen more clearly than distant objects because distant objects focus in front of the retina.

Farsightedness

A condition in which far-away objects are seen more clearly than near objects because the image of near objects is focused behind the retina.

Retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to colour sensations.

Optic Nerve

The nerve that carries neural impulses from the eye to the brain.

Blind Spot

The point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there.

Fovea

The central focal point in the retina, around which the eye's cones cluster.

Feature Detectors

Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement.

Parallel Processing

The processing of several aspects of a problem simultaneously; the brain's natural mode of information processing for many functions, including vision. Contrasts with the step-by-step (serial) processing of most computers and of conscious problem solving.

Young-Helmholtz Trichromatic Theory

The theory that the retina contains three different colour receptors- one most sensitive to red, one to green, one to blue- which when stimulated in combination can produce the perception of any colour.

Opponent-Process Theory

Theory that opposing retinal processes (red-green, yellow-blue, white-black) enable colour vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green.

Color Constancy

Perceiving familiar objects as having consistent colour, even if changing illumination alters the wavelengths reflected by the object.

Audition

The sense or act of hearing.

Frequency

The number of complete wavelengths that pass a point in a given time (for example, per second).

Pitch

A tone's experienced highness or lowness; depends on frequency.

Middle Ear

The chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window.

Cochlea

A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses.

Inner Ear

The innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs.

Place Theory

In hearing, the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated.

Frequency Theory

In hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch.

Conduction Hearing Loss

Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.

Sensorineural Hearing Loss

Hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves; also called nerve deafness.

Cochlear Implant

A device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea.

Gate-Control Theory

The theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain. The "gate" is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain.

Sensory Interaction

The principle that one sense may influence another, as when the smell of food influences its taste.

Kinesthesis

The system for sensing the position and movement of individual body parts.

Vestibular Sense

The sense of body movement and position, including the sense of balance.

Selective Attention

The focusing of conscious awareness on a particular stimulus, as in the cocktail party effect.

Inattentional Blindness

Failing to see visible objects when our attention is directed elsewhere.

Visual Capture

The tendency for vision to dominate the other senses.

Gestalt

An organized whole. These psychologists emphasize our tendency to integrate pieces of information into meaningful wholes.

Figure-Ground

The organization of the visual field into objects (the figures) that stand out from their surroundings (the ground).

Grouping

The perceptual tendency to organize stimuli into coherent groups.

Depth Perception

The ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance.

Visual Cliff

A laboratory device for testing depth perception in infants and young animals.

Binocular Cues

Depth cues, such as retinal disparity and convergence, that depend on the use of two eyes.

Retinal Disparity

A binocular cue for perceiving depth: By comparing images from the two eyeballs, the brain computes distance- the greater the disparity (difference) between the two images, the clearer the object.

Convergence

A binocular cue for perceiving depth; the extent to which the eyes converge inward when looking at an object. The greater the inward strain, the closer the object.

Monocular Cues

Depth cues, such as interposition and linear perspective, available to either eye alone.

Phi Phenomenon

An illusion of movement created when two or more adjacent lights blink on and off in quick succession.

In vision, the ability to adjust to an artificially displaced or even inverted visual field.

Perceptual Set

A mental predisposition to perceive one thing and not another.

Human Factors Psychology

A branch of psychology that explores how people and machines interact and how machines and physical environments can be made safe and easy to use.

Extrasensory Perception (ESP)

The controversial claim that perception can occur apart from sensory input. Said to include telepathy, clairvoyance, and precognition.

Parapsychology

The study of paranormal phenomena, including ESP and psychokinesis.

Consciousness

Our awareness of ourselves and our environment.

Biological Rhythms

Periodic physiological fluctuations.

Circadian Rhythm

The biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a 24-hour cycle.

REM (Rapid Eye Movement) Sleep

A recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active.

Alpha Waves

The relatively slow brain waves of a relaxed, awake state.

Sleep

Periodic, natural, reversible loss of consciousness - as distinct from unconsciousness resulting from a coma, general anaesthesia, or hibernation.

Hallucinations

False sensory experiences, such as seeing something in the absence of an external visual stimulus.

Delta Waves

The large, slow brain waves associated with deep sleep.

Insomnia

Recurring problems in falling or staying asleep.

Narcolepsy

A sleep disorder characterized by uncontrollable sleep attacks. The sufferer may lapse directly into REM sleep, often at inopportune times.

Sleep Apnea

A sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary reawakenings.

Night Terrors

A sleep disorder characterized by high arousal and an appearance of being terrified; unlike nightmares, these occur during Stage 4 sleep, within two or three hours of falling asleep, and are seldom remembered.

Dream

A sequence of images, emotions, and thoughts passing through a sleeping person's mind. They are notable for their hallucinatory imagery, discontinuities, and incongruities, and for the dreamer's delusional acceptance of the content and later difficulties remembering it.

Manifest Content

According to Freud, the remembered story line of a dream (as distinct from its hidden content).

Latent Content

According to Freud, the underlying meaning of a dream (as distinct from its other content). Freud believed that a dream's ______content functions as a safety valve.

A powerfully addictive drug that stimulates the central nervous system, with speeded-up body functions and associated energy and mood changes; over time, appears to reduce baseline dopamine levels.

Ecstasy

A synthetic stimulant and mild hallucinogen. Produces euphoria and social intimacy, but with short-term health risks and longer-term harm to serotonin-producing neurons and to mood and cognition.

Hallucinogens

Psychedelic ("mind manifesting") drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input.

LSD

A powerful hallucinogenic drug; also known as acid (lysergic acid diethylamide).

THC

The major active ingredient in marijuana; triggers a variety of effects, including mild hallucinations.

Near-Death Experience

An altered state of consciousness reported after a close brush with death (such as through cardiac arrest); often similar to drug-induced hallucinations.

Dualism

The presumption that mind and body are two distinct entities that interact.

Monism

The presumption that mind and body are different aspects of the same thing.

Learning

A relatively permanent change in an organism's behavior due to experience.

Associative Learning

Learning that certain events occur together. The events may be two stimuli (as in classical conditioning) or a response and its consequences (as in operant conditioning).

Classical Conditioning

A type of learning in which an organism comes to associate stimuli. A neutral stimulus that signals an unconditioned stimulus (US) begins to produce a response that anticipates and prepares for the unconditioned stimulus. Also called Pavlovian or respondent conditioning.

Behaviorism

The view that psychology (1) should be an objective science that (2) studies behavior without reference to mental processes. Most research psychologists today agree with (1) but not with (2).

Unconditioned Response

In classical conditioning, the unlearned, naturally occurring response to the unconditioned stimulus (US), such as salivation when food is in the mouth.

Unconditioned Stimulus

In classical conditioning, a stimulus that unconditionally- naturally and automatically- triggers a response.

Conditioned Response

In classical conditioning, the learned response to a previously neutral (but now conditioned) stimulus (CS).

Conditioned Stimulus

In classical conditioning, an originally irrelevant stimulus that, after association with an unconditioned stimulus (US), comes to trigger a conditioned response.

Acquisition

The initial stage in classical conditioning; the phase associating a neutral stimulus with an unconditioned stimulus so that the neutral stimulus comes to elicit a conditioned response. In operant conditioning, the strengthening of a reinforced response.

Extinction

The diminishing of a conditioned response; occurs in classical conditioning when an unconditioned stimulus (US) does not follow a conditioned stimulus (CS); occurs in operant conditioning when a response is no longer reinforced.

Spontaneous Recovery

The reappearance, after a pause, of an extinguished conditioned response.

Generalization

The tendency, once a response has been conditioned, for stimuli similar to the conditioned stimulus to elicit similar responses.

Discrimination

In classical conditioning, the learned ability to distinguish between a conditioned stimulus and stimuli that do not signal an unconditioned stimulus.

Operant Conditioning

A type of learning in which behavior is strengthened if followed by a reinforcer or diminished if followed by a punisher.

Respondent Behavior

Behavior that occurs as an automatic response to some stimulus; Skinner's term for behavior learned through classical conditioning.

Operant Behavior

Behavior that operates on the environment, producing consequences.

Law of Effect

Thorndike's principle that behaviors followed by favorable consequences become more likely, and that behaviors followed by unfavorable consequences become less likely.

Operant Chamber

: A chamber also known as a Skinner box, containing a bar or key that an animal can manipulate to obtain a food or water reinforcer, with attached devices to record the animal's rate of bar pressing or key pecking. Used in operant conditioning research.

Shaping

An operant conditioning procedure in which reinforcers guide behavior toward closer and closer approximations of the desired behavior.

Reinforcer

In operant conditioning, any event that strengthens the behavior it follows.

Positive Reinforcement

Increasing behaviors by presenting positive stimuli, such as food. A positive reinforcer is any stimulus that, when presented after a response, strengthens the response.

Negative Reinforcement

Increasing behaviors by stopping or reducing negative stimuli, such as shock. A negative reinforcer is any stimulus that, when removed after a response, strengthens the response. (Note: this is different from punishment.)

Primary Reinforcer

An innately reinforcing stimulus, such as one that satisfies a biological need.

Conditioned Reinforcer

A stimulus that gains its reinforcing power through its association with a primary reinforcer; also known as secondary reinforcer.

Continuous Reinforcement

Reinforcing the desired response every time it occurs

Partial Reinforcement

Reinforcing a response only part of the time; results in slower acquisition of a response but much greater resistance to extinction than does continuous reinforcement.

Fixed-Ratio Schedule

In operant conditioning, a reinforcement schedule that reinforces a response only after a specified number of responses.

Variable-Ratio Schedule

In operant conditioning, a reinforcement schedule that reinforces a response after an unpredictable number of responses.

Fixed-Interval Schedule

In operant conditioning, a reinforcement schedule that reinforces a response only after specified time has elapsed.

Variable-Interval Schedule

In operant conditioning, a reinforcement schedule that reinforces a response at unpredictable time intervals.

Punishment

An event that decreases the behavior that it follows.

Cognitive Map

A mental representation of the layout of one's environment. For example, after exploring a maze, rats act as if they have learned a cognitive map of it.

Latent Learning

Learning that occurs but is not apparent until there is an incentive to demonstrate it.

Intrinsic Motivation

A desire to perform a behavior for its own sake.

Extrinsic Motivation

A desire to perform a behavior due to promised rewards or threats of punishment.

Observational Learning

Learning by observing others.

Modeling

The process of observing and imitating a specific behavior.

Mirror Neurons

Frontal lobe neurons that fire when performing certain actions or when observing another doing so. The brain's mirroring of another's action may enable imitation, language learning, and empathy.

Memory of facts and experiences that one can consciously know and "declare." (Also called declarative memory.)

Hippocampus

A neural center that is located in the limbic system and helps process explicit memories for storage.

Recall

A measure of memory in which the person must retrieve information learned earlier, as on a fill-in-the-blank test.

Recognition

A measure of memory in which the person need only identify items previously learned, as on a multiple choice test.

Relearning

A memory measure that assesses the amount of time saved when learning material for a second time.

Priming

The activation, often unconsciously, of particular associations in memory. Ask a friend two rapid-fire questions: (a) How do you pronounce the word spelled by the letters s-h-o-p? (b) What do you do when you come to a green light? If your friend answers "stop" to the second question, you have demonstrated priming.

Déjà Vu

That eerie sense that "I've experienced this before." Cues from the current situation may subconsciously trigger retrieval of an earlier experience.

Mood-Congruent Memory

The tendency to recall experiences that are consistent with one's current good or bad mood.

Proactive Interference

The disruptive effect of prior learning on the recall of new information.

Retroactive Interference

The disruptive effect of new learning on the recall of old information.

Repression

In psychoanalytic theory, the basic defence mechanism that banishes from consciousness anxiety-arousing thoughts, feelings, and memories.

Misinformation Effect

Incorporating misleading information into one's memory of an event.

Source Amnesia

Attributing to the wrong source an event we have experienced, heard about, read about, or imagined. (Also called source misattribution.) It, along with the misinformation effect, is at the heart of many false memories.

Cognition

The mental activities associated with thinking, knowing, remembering, and communicating.

Concept

A mental grouping of similar objects, events, ideas, or people.

Prototype

A mental image or best example of a category. Matching new items to the it provides a quick and easy method for including items in a category (as when comparing feathered creatures to a prototypical bird, such as a robin).

Algorithm

A methodical, logical rule or procedure that guarantees solving a particular problem. Contrasts with the usually speedier- but also more error-prone- use of heuristics.

Heuristic

A simple thinking strategy that often allows us to make judgements and solves problems efficiently; usually speedier but also more error-prone than algorithms.

Insight

A sudden and often novel realization of the solution to a problem; it contrasts with strategy-based solutions.

Confirmation Bias

A tendency to search for information that confirms one's preconceptions.

Fixation

The inability to see a problem from a new perspective; an impediment to problem solving.

Mental Set

A tendency to approach a problem in a particular way, often a way that has been successful in the past.

Functional Fixedness

The tendency to think of things only in terms of their usual functions; an impediment to problem solving.

Representativeness Heuristic

Judging the likelihood of things in terms of how well they seem to represent, or match, particular prototypes, may lead one to ignore other relevant information.

Availability Heuristic

Estimating the likelihood of events based on their availability in memory, if instances come readily to mind (perhaps because of their vividness), we presume such events are common.

Overconfidence

The tendency to be more confident than correct, to overestimate the accuracy of one's beliefs and judgments.

Framing

The way an issue is posed, how an issue is framed can significantly affect decisions and judgments.

Clinging to one's initial conceptions after the basis on which they were formed has been discredited.

Language

Our spoken, written, or signed words and the ways we combine them to communicate meaning.

Phoneme

In a language, the smallest distinctive sound unit.

Morpheme

In a language, the smallest unit that carries meaning, may be a word or a part of a word (such as a prefix).

Grammar

In a language, a system of rules that enables us to communicate with and understand others.

Semantics

The set of rules by which we derive meaning from morphemes, words and sentences in a given language; also, the study of meaning.

Syntax

The rules for combining words into grammatically sensible sentences in a given language.

Babbling Stage

Beginning at about 4 months, the stage of speech development in which the infant spontaneously utters various sounds at first unrelated to the house-hold language.

One-Word Stage

The stage in speech development, from about age 1 to 2, during which a child speaks mostly in single words.

Two-Word Stage

Beginning about age 2, the stage in speech development during which a child speaks mostly two-word statements.

Telegraphic Speech

Early speech stage in which a child speaks like a telegram- "go car"- using mostly nouns and verbs and omitting auxiliary words.

Linguistic Determinism

Whorf's hypothesis that language determines the way we think.

Intelligence

mental qualities consisting of the ability to learn from experience, solve problems, and use knowledge to adapt to new situations.

Factor Analysis

A statistical procedure that identifies clusters of related items (called factors) on a test; used to identify different dimensions of performance that underlie one's total score.

General Intelligence

A general intelligence factor that according to Spearman and others underlies specific mental abilities and is therefore measured by every task on an intelligence test.

Savant Syndrome

A condition in which a person otherwise limited in mental ability has an exceptional specific skill, such as in computation or drawing.

Emotional Intelligence

The ability to perceive, understand, manage, and use emotions.

Creativity

The ability to produce novel and valuable ideas.

Intelligence Test

A method for assessing an individual's mental aptitudes and comparing them with those of others, using numerical scores.

Mental Age

A measure of intelligence test performance devised by Binet; the chronological age that most typically corresponds to a given level of performance. Thus, a child who does as well as the average 8-year-old is said to have a mental age of 8.

Stanford-Binet

The widely used American revision (by Terman at Stanford University) of Binet's original intelligence test.

Intelligence Quotient

Defined originally as the ratio of mental age (ma) to chronological age (ca) multiplied by 100. On contemporary intelligence tests, the average performance for a given age is assigned a score of 100.

Aptitude Test

A test designed to predict a person's future performance; aptitude is the capacity to learn.

Achievement Test

A test designed to assess what a person has learned.

Wechsler Adult Intelligence Scale

Is the most widely used intelligence test; contains verbal and performance (nonverbal) subtests.

Standardization

Defining meaningful scores by comparison with the performance of a pretested standardization group.

Normal Curve

The symmetrical bell-shaped curve that describes the distribution of many physical and psychological attributes. Most scores fall near the average, and fewer and fewer scores lie near the extremes.

Reliability

The extent to which a test yields consistent results, as assessed by the consistency of scores on two halves of the test, on alternate forms of the test, or on retesting.

Criterion

The behavior (such as future college grades) that a test (such as SAT) is designed to predict; thus, the measure used in defining whether the test has predictive validity.

Predictive Validity

The success with which a test predicts the behavior it is designed to predict; it is assessed by computing the correlation between test scores and the criterion behavior. (Also called criterion-related validity.)

Mental Retardation

A condition of limited mental ability, indicated by an intelligence score of 70 or below and difficulty in adapting to the demands of life; varies from mild to profound.

Down Syndrome

A condition of retardation and associated physical disorders caused by an extra chromosome in one's genetic makeup.

Stereotype Threat

A self-confirming concern that one will be evaluated based on a negative stereotype.

Validity

The extent to which a test measures or predicts what it is supposed to.

Content Validity

The extent to which a test samples the behavior that is of interest (such as a driving test that samples driving tasks).

Motivation

A need or desire that energizes and directs behavior.

Instinct

A complex behaviour that is rigidly patterned throughout a species and is unlearned.

Drive-Reduction Theory

The idea that a physiological need creates an aroused tension state (a drive) that motivates an organism to satisfy the need.

Homeostasis

A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level.

Incentive

A positive or negative environmental stimulus that motivates behavior.

Hierarchy of Needs

Maslow's pyramid of human needs, beginning at the base with physiological needs that must first be satisfied before higher-level safety needs and then psychological needs become active.

Glucose

The form of sugar that circulates in the blood and provides the major source of energy for body tissues. When its level is low, we feel hunger.

Set Point

The point at which an individual's "weight thermostat" is supposedly set. When the body falls below this weight, an increase in hunger and a lowered metabolic rate may act to restore the lost weight.

Basal Metabolic Rate

The body's resting rate of energy expenditure.

Anorexia Nervosa

An eating disorder in which a normal-weight person (usually an adolescent female) diets and becomes significantly (15 percent or more) underweight, yet, still feeling fat, continues to starve.

Bulimia Nervosa

An eating disorder characterized by episodes of overeating, usually of high-calorie foods, followed by vomiting, laxative use, fasting, or excessive exercise.

Sexual Response Cycle

The four stages of sexual responding described by Masters and Johnson- excitement, plateau, orgasm, and resolution (EPOR, rope backwards).

Refractory Period

A resting period after orgasm, during which a man cannot achieve another orgasm.

The most important of the male sex hormones. Both males and females have it, but the additional testosterone in males stimulates the growth of the male sex organs in the fetus and the development of the male sex characteristics during puberty.

Sexual Orientation

An enduring sexual attraction toward members of either one's own sex (homosexual orientation) or the other sex (heterosexual orientation).

Flow

A completely involved, focused state of consciousness, with diminished awareness of self and time, resulting from optimal engagement of one's skills.

Industrial-Organizational Psychology

The application of psychological concepts and methods to optimizing human behavior in workplaces.

Self-perceived happiness or satisfaction with life. Used along with measures of objective well-being (for example, physical and economic indicators) to evaluate people's quality of life.

Adaptation-Level Phenomenon

Our tendency to form judgements (of sounds, of lights, of income) relative to a neutral level defined by our prior experience.

Relative Deprivation

The perception that one is worse off relative to those with whom one compares oneself.

Behavioral Medicine

An interdisciplinary field that integrates behavioral and medical knowledge and applies that knowledge to health and disease.

Health Psychology

A subfield of psychology that provides psychology's contribution to behavioral medicine.

Stress

The process by which we perceive and respond to certain events, called stressors, that we appraise as threatening or challenging.

General Adaptation Syndrome (GAS)

Selye's concept of the body's adaptive response to stress in three stages- alarm, resistance, exhaustion (ARE).

Coronary Heart Disease

The clogging of the vessels that nourish the heart muscle (semicolon -insert-) the leading cause of death in many developed countries.

Type A

Friedman and Rosenman's term for competitive, hard-driving, impatient, verbally aggressive, and anger-prone people.

Type B

Friedman and Rosenman's term for easygoing, relaxed people.

Psychophysiological Illness

Literally, "mind-body" illness; any stress-related physical illness, such as hypertension and some headaches. (Note: This is distinct from hypochondriasis- misinterpreting normal physical sensations as symptoms of a disease.)

Lymphocytes

The two types of white blood cells that are part of the body's immune system: B lymphocytes form in the bone marrow and release antibodies that fight bacterial infections (semicolon -insert-) T lymphocytes form in the thymus and other lymphatic tissue and attack cancer cells, viruses, and foreign substances.

Coping

Alleviating stress using emotional, cognitive, or behavioral methods.

Problem-Focused Coping

Attempting to alleviate stress directly- by changing the stressor or the way we interact with that stressor.

Emotion-Focused Coping

Attempting to alleviate stress by avoiding or ignoring a stressor and attending to emotional needs related to one's stress reaction.

Aerobic Exercise

Sustained exercise that increases heart and lung fitness (semicolon -insert-) may also alleviate depression and anxiety.

Biofeedback

A system for electronically recording, amplifying, and feeding back information regarding a subtle physiological state, such as blood pressure or muscle tension.

Complementary and Alternative Medicine

Unproven health care treatments not taught widely in medical schools, not used in hospitals, and not usually reimbursed by insurance companies.

Personality

An individual's characteristic pattern of thinking, feeling, and acting.

Free Association

In psychoanalysis, a method of exploring the unconscious in which the person relaxes and says whatever comes to mind, no matter how trivial or embarrassing.

Psychoanalysis

Freud's theory of personality that attributes thoughts and actions to unconscious motives and conflicts (semicolon -insert-) the techniques used in treating psychological disorders by seeking to expose and interpret unconscious tensions.

Unconscious

According to Freud, a reservoir of mostly unacceptable thoughts, wishes, feelings, and memories. According to contemporary psychologists, information processing of which we are unaware.

Id

Contains a reservoir of unconscious psychic energy that, according to Freud, strives to satisfy basic sexual and aggressive drives. It operates on the pleasure principle, demanding immediate gratification.

Ego

The largely conscious, "executive" part of the personality that, according to Freud, mediates among the demands of the id, superego, and reality. It operates on the reality principle, satisfying the id's desires in ways that will realistically bring pleasure rather than pain.

Superego

The part of personality that, according to Freud, represents internalized ideals and provides standards for judgment (the conscience) and for future aspirations.

Psychosexual Stages

The childhood stages of development (oral, anal, phallic, latency, genital) during which, according to Freud, the id's pleasure-seeking energies focus on distinct erogenous zones.

Oedipus Complex

According to Freud, a boy's sexual desires toward his mother and feelings of jealousy and hatred for the rival father.

Identification

The process by which, according to Freud, children incorporate their parents' values into their developing superegos.

Fixation

According to Freud, a lingering focus of pleasure-seeking energies at an earlier psychosexual stage, in which conflicts were unresolved.

In psychoanalytic theory, the basic defence mechanism that banishes anxiety-arousing thoughts, feelings, and memories from consciousness.

Regression

Psychoanalytic defense mechanism in which an individual faced with anxiety retreats to a more infantile psychosexual stage, where some psychic energy remains fixated.

Reaction Formation

Psychoanalytic defense mechanism by which the ego unconsciously switches unacceptable impulses into their opposites. Thus, people may express feelings that are the opposite of their anxiety-arousing unconscious feelings.

Projection

Psychoanalytic defense mechanism by which people disguise their own threatening impulses by attributing them to others.

Rationalization

Defense mechanism that offers self-justifying explanations in place of the real, more threatening, unconscious reasons for one's actions.

Displacement

Psychoanalytic defense mechanism that shifts sexual or aggressive impulses toward a more acceptable or less threatening object or person, as when redirecting anger toward a safer outlet.

Collective Unconscious

Carl Jung's concept of a shared, inherited reservoir of memory traces from our species' history.

Projective Test

A personality test, such as the Rorschach or TAT, that provides ambiguous stimuli designed to trigger projection of one's inner dynamics.

Thematic Apperception Test

A projective test in which people express their inner feelings and interests through the stories they make up about ambiguous scenes.

Rorschach Inkblot Test

The most widely used projective test, a set of 10 inkblots, designed by Hermann Rorschach (semicolon -insert-) seeks to identify people's inner feelings by analyzing their interpretations of the blots.

Terror-Management Theory

Proposes that faith in one's worldview and the pursuit of self-esteem provide protection against a deeply rooted fear of death.

Self-Actualization

According to Maslow, the ultimate psychological need that arises after basic physical and psychological needs are met and self-esteem is achieved (semicolon -insert-) the motivation to fulfill one's potential.

Unconditional Positive Regard

According to Rogers, an attitude of total acceptance toward another person.

Self-Concept

All our thoughts and feelings about ourselves, in answer to the question, "Who am I?"

Trait

A characteristic pattern of behavior or a disposition to feel and act, as assessed by self-report inventories and peers report.

Personality Inventory

A questionnaire (often with true-false or agree-disagree items) on which people respond to items designed to gauge a wide range of feelings and behaviors (semicolon -insert-) used to assess selected personality traits.

Minnesota Multiphasic Personality Inventory

The most widely researched and clinically used of all personality test. Originally developed to identify emotional disorders (still considered its most appropriate use), this test is now used for many other screening purposes.

Empirically Derived Test

A test (such as the MMPI) developed by testing a pool of items and then selecting those that discriminate between groups.

Social-Cognitive Perspective

Views behavior as influenced by the interaction between persons (and their thinking) and their social context.

Reciprocal Determinism

The interacting influences between personality and environment factors.

Personal Control

Our sense of controlling our environment rather than feeling helpless.

A psychological disorder marked by the appearance by age 7 of one or more of three key symptoms: extreme inattention, hyperactivity, and impulsivity.

Medical Model

The concept that diseases have physical caused that can be diagnosed, treated, and, in most cases, cured. When applied to psychological disorders, the medical model assumes that these mental illnesses can be diagnosed on the basis of their symptoms and cured through therapy, which may include treatment in a psychiatric hospital.

A rare dissociative disorder in which a person exhibits two or more distinct and alternating personalities. (Also called multiple personality disorder.)

Mood Disorders

Psychological disorders characterized by emotional extremes.

Major Depressive Disorder

A mood disorder in which a person experiences, in the absence of drugs or a medical condition, two or more weeks of significantly depressed moods, feelings of worthlessness, and diminished interest or pleasure in most activities.

Mania

A mood disorder marked by a hyperactive, wildly optimistic state.

Bipolar Disorder

A mood disorder in which the person alternates between the hopelessness and lethargy of depression and the overexcited state of mania. (Formerly called manic-depressive disorder.)

Schizophrenia

A group of severe disorders characterized by disorganized and delusional thinking, disturbed perceptions, and inappropriate emotions and actions.

Delusions

False beliefs, often of persecution or grandeur, that may accompany psychotic disorders.

Personality Disorders

Psychological disorders characterized by inflexible and enduring behaviour patterns that impair social functioning.

Antisocial Personality Disorder

A personality disorder in which the person (usually a man) exhibits a lack of conscience for wrongdoing, even toward friends and family members. May be aggressive and ruthless or a clever con artist.

Psychotherapy

An emotionally charged, confiding interaction between a trained therapist and someone who suffers from psychological difficulties.

Biomedical Therapy

Prescribed medications or medical procedures that act directly on the patient's nervous system.

Eclectic Approach

An approach to psychotherapy that, depending on the client's problems, uses techniques from various forms of therapy.

In psychoanalysis, the blocking from consciousness of anxiety-laden material.

Interpretation

In psychoanalysis, the analyst's noting supposed dream meanings, resistances, and other significant behaviors and events in order to promote insight.

Transference

In psychoanalysis, the patient's transfer to the analyst of emotions linked with other relationships (such as love or hatred for a patient).

Client-Centered Therapy

A humanistic therapy, developed by Carl Rogers, in which the therapist uses techniques such as active listening within a genuine, accepting, empathic, environment to facilitate clients' growth. (Also called person-centered therapy.)

Active Listening

Empathic listening in which the listener echoes, restates, and clarifies. A feature of Rogers' client-centered therapy.

Behavior Therapy

Therapy that applies learning principles to the elimination of unwanted behaviors.

Counterconditioning

A behavior therapy procedure that conditions new responses to stimuli that trigger unwanted behaviors

Exposure Therapies

Behavioural techniques, such as systematic desensitization, that treat anxieties by exposing people (in imagination or actuality) to the things they fear and avoid.

Systematic Desensitization

A type of counterconditioning that associates a pleasant relaxed state with gradually increasing anxiety-triggering stimuli. Commonly used to treat phobias.

Virtual Reality Exposure Therapy

An anxiety treatment that progressively exposes people to simulations of their greatest fears, such as airplane flying, spiders, or public speaking.

Aversive Conditioning

A type of counterconditioning that associates an unpleasant state( such as nausea) with an unwanted behavior (such as drinking alcohol).

Token Economy

An operant conditioning procedure in which people earn a token of some sort for exhibiting a desired behaviour and can later exchange the tokens for various privileges or treats.

Cognitive Therapy

Therapy that teaches people new, more adaptive ways of thinking and acting based on the assumption that thoughts intervene between events and our emotional reactions.

Therapy that treats the family as system. Views an individual's unwanted behaviors as influenced by or direct at other family members; attempts to guide family members toward positive relationships and improved communication.

Regression Toward the Mean

The tendency for extremes of unusual scores to fall back toward their average.

Meta-Analysis

A procedure for statistically combining the results of many different research studies.

Psychopharmacology

The study of the effects of drugs on mind and behavior.

Tardive Dyskinesia

Involuntary movements of the facial muscles, tongue, and limbs a possible neurotoxic side effect of long-term use of antipsychotic drugs that target D2 dopamine receptors.

Electroconvulsive Therapy

A biomedical therapy for severely depressed patients in which a brief electric current is sent through the brain of an anesthetised patient.

Repetitive Transcranial Magnetic Stimulation

The application of repeated pulses of magnetic energy to the brain (semicolon -insert-) used to stimulate or suppress brain activity.

Psychosurgery

Surgery that removes or destroys brain tissue in an effort to change behaviour.

Lobotomy

A now-rare psychosurgical procedure once used to calm uncontrollably emotional or violent patients. The procedure cut the nerves that connect the frontal lobes to the emotion-controlling centers of the inner brain.

Social Psychology

The scientific study of how we think about, influence, and relate to one another.

Attribution Theory

Suggests how we explain someone's behavior- by crediting either the situation or the person's disposition.

Fundamental Attribution Error

The tendency for observers, when analyzing another's behavior, to underestimate the impact of the situation and to overestimate the impact of personal disposition.

Attitude

Feelings, often based on our beliefs, that predispose us to respond in a particular way to objects, people, and events.

Foot-in-the-Door Phenomenon

The tendency for people who have first agreed to a small request to comply later with a larger request.

Cognitive Dissonance Theory

The theory that we act to reduce the discomfort (dissonance) we feel when two of our thoughts (cognitions) are inconsistent. For example, when our awareness of our attitudes and of our actions clash, we can reduce the resulting dissonance by changing our attitudes.

Conformity

Adjusting one's behavior or thinking to coincide with a group standard.

Normative Social Influence

Influence resulting from a person's desire to gain approval or avoid disapproval.